Jump to ratings and reviews
Rate this book

Fractions in Disguise: A Math Adventure

Rate this book
Crack the case with George Cornelius Factor in this entertaining math adventure that introduces simplified and reduced fractions with equal parts intrigue and humor.

When a valuable fraction goes missing, George Cornelius Factor (a.k.a. GCF) vows to track it down. Knowing that the villainous Dr. Brok likes to disguise his ill-gotten fractions, GCF invents a Reducer—half ray gun, half calculator— that strips away the disguise, reducing the fraction to its lowest common denominator and revealing its true form. With the Reducer in hand, George seeks out Dr. Brok in hopes of retrieving the missing fraction.

Back matter includes more detail on simplifying, or reducing, fractions.

32 pages, Hardcover

First published January 1, 2014

Loading interface...
Loading interface...

About the author

Edward Einhorn

16 books22 followers
Edward Einhorn is a writer/theater director, based in New York. He has written plays about neurology; picture books about math; adaptations of sci-fi novels; translations of French and Czech absurdists and of ancient Greek drama; puppet theater; modern Oz novels; explorations of economic theory; autobiographical found text dramas; midrashim on Jewish cultural icons; a libretto for an oratorio; and other texts of a less definable nature. He is also the Artistic Director of a theater company, Untitled Theater Company #61: a Theater of Ideas.

Ratings & Reviews

What do you think?
Rate this book

Friends & Following

Create a free account to discover what your friends think of this book!

Community Reviews

5 stars
67 (36%)
4 stars
58 (31%)
3 stars
44 (23%)
2 stars
13 (6%)
1 star
4 (2%)
Displaying 1 - 30 of 48 reviews
Profile Image for Esther.
277 reviews
Read
May 8, 2015
Great use of puns. Also teaches the reduction by factoring, but through solving a mystery and more plot-based than a straight solution.
This entire review has been hidden because of spoilers.
Profile Image for Emily Foster.
125 reviews2 followers
October 8, 2019
The premise of this book is really nice, I really like how fractions are incorporated throughout and particularly how it includes mathematical definitions, language and some misconceptions (5/9 looks like a half but is just more). However, I found the book too wordy and quite hard to follow and could be so much easier if the really helpful and engaging illustrations were partnered with fewer words.
Profile Image for Rachel.
2,835 reviews58 followers
August 27, 2014
The author asked if I would review his newest math adventure book. I accepted as I enjoy his authorship of "Paradox in Oz". I am not a big math fan, but I was pleasantly surprised by this book and its fun and amusing puns. I also loved the illustrations by David Clark. It would be great for a reluctant reader who likes math or to use in a classroom to help kids understand how to simplify fractions. There is a longer description of fraction reduction in the back of the book.

The book is about a young man named George Cornelius Factor, who is part of a small group of fraction collectors, and is very interested in acquiring the fraction 5/8. It is stolen by Dr. Brok, who immediately changes it to make it unrecognizable. But all hope is not lost. Factor invents “The Reducer” which reduces a fraction to its lowest terms and uncovers the missing fraction. He proudly displays his newest acquisition to collection afterwards. Recommended for ages 7-10, 4 stars.
Profile Image for Barbara.
13.7k reviews288 followers
March 3, 2014
Math teachers may want to add this book to their collection since it teaches about fractions in an entertaining way. George Cornelius Factor loves fractions; in fact, he even collects them. But when one that he has his eye on disappears, he confronts the mysterious Dr. Brok about its location. There is plenty of humor and lots of action and colorful illustrations even while students are learning about how to reduce fractions.
Profile Image for Cindy Minnich.
145 reviews33 followers
July 3, 2014
I'm not sure what made me pick this book up, but I know that I was delighted when I saw my son's eyes light up - a sign that he'd figured something new out about the world. This book has a silly pun-filed whodunnit, an invention, and a great way to explain how and why to reduce fractions. I'm not sure what my elementary math teacher friends would say about it, but seeing this concept make sense to my son seemed good enough for me.
Profile Image for Diane.
7,097 reviews
July 6, 2017
George Cornelius Factor is a collector of fractions. George, who is 1/4 genius, 1/ stubborn, 1/3 determined and 1/6 crazy, goes to auctions in search of new fractions for his collection. And when someone steals the 5/9 that is being auctioned, George builds a "reducer" (1/2 ray gun and 1/2 calculator) in order to find the fraction that has been disguised.

A fun way to introduce students to reducing fractions. I'm anxious to show this one to my teachers to see what they think.
Profile Image for Margaret.
2,640 reviews
May 19, 2014
In fact there are even people who collect fractions. I know it's hard to believe it's true but in Fractions in Disguise: A Mathematical Adventure (Charlesbridge) written by Edward Einhorn with illustrations by David Clark, three people are victims of an evil mind.

Full review: http://bit.ly/1iVCU8f
Profile Image for Kate Hastings.
2,128 reviews41 followers
August 8, 2014
Grades 3-5. Reducing fractions has never been so fun! A fraction has been stolen from a math auction and the thief has disguised it by creating an equivalent fraction. George Cornelius Factor invents the "Reducer" to help identify the stolen fraction and save the day. It would be fun to have students create their own "reducer rays" and act out the story with other fractions.
Profile Image for Sabrina.
201 reviews17 followers
January 31, 2015
Cute story about reducing/simplifying fractions. Love the illustrations and creative names! This book might be good for a 3rd-4th grade read aloud. I would give this book 5 stars, but the transition between the pages didn't go as smoothly as I would have liked. However,it is still a good book for the subject and I still recommend it!
Author 1 book64 followers
June 6, 2014
This is a great book for students who are learning about fractions! There are fractions on every page, jokes to go with them, and a mystery to solve. In order to solve the mystery, though, one must know about fractions. It's a fabulous and fun read for elementary school students!
Profile Image for The Brothers.
4,118 reviews23 followers
January 28, 2016
Asher (8yo) got a LOT more out of this book than Dexter (5yo), though Dexter seemed to enjoy it nonetheless and sat through it without complaint. A collector of fractions hunts down a stolen one by using a device he constructed called the Reducer.

The illustrations really are superb.
1,846 reviews15 followers
May 27, 2014
This was a book that incorporated upper elementary math, and there certainly aren't many of them. The illustrator is from Va.!
Profile Image for Maria Caplin.
397 reviews12 followers
Read
August 7, 2014
Fun story could be interactive with students using dry erase boards. Fun addition to math workshop mentor text.
Profile Image for Kaitlyn.
16 reviews11 followers
February 14, 2015
I thought this was positively charming! I loved the puns, the pictures, and the characters. This really made me smile. Over all a fun read.
Profile Image for Trever.
588 reviews12 followers
May 7, 2015
A wonderful book about simplifying fractions and leads into discussions about adding fractions. A book for any middle level to upper elementary math teacher. Excellent classroom resource.
Profile Image for Jen Yonit.
383 reviews6 followers
December 7, 2015
My 8 and 9 year olds loved this book. They have read and reread it. Definitely going to look out for more books by this author!
638 reviews2 followers
June 20, 2016
This is a great book for teaching equivalent and reducing fractions, with a cute story to go with it.
Profile Image for Jenny.
572 reviews4 followers
March 20, 2017
This was a cute idea. It did a decent job of making what could be a dry subject into something more fun. If you are a math nerd, you can get your nerd on.
Profile Image for Rebeca Sanchez.
99 reviews1 follower
December 5, 2020
For those who read or known about Richie-Rich, he has a cousin who loves fractions. He explains his fractions by representing this with the use of pie graphs and mounting them on pedestals. One example is seen when he comes for an auction, he bids for 1/2 of a million dollars but a bidder steals the object that was bidded. George uses a set of different objects with 1/2 and other fractions to remove the stealer's disguise. There is a mystery and uncovering the truth to the story, so the boy finds the treasures and reduces major fractions to their unit fractions. This is a truly engaging story and it may have the students understand fractions much more. The use of ink and watercolors build the humor of the story, but it also builds on the sense of drama. There are some pages that have some wordy explanations that may confuse the readers. As I was reading the story, I did get lost through the story since it lost its momentum. In the use of the book, I would use it with much simpler explanations since it does get confused about how fractions are taught. I would use the visuals used and have the students compare it to the story and stop throughout the story- for clarification.
Profile Image for Sarah Rogers.
100 reviews1 follower
May 15, 2023
This book tells the strange story of a young boy and his mission to convert fractions to their simplest form. Trying to win an award, he makes a machine that will always make fractions into lowest terms. Hi machine can zap any divided pie into it’s simplest form. We see how he goes to Dr. Brok to find the 5/9 and after looking around and simplifying everything he can he finds the missing piece and zaps the large fraction into simplest form of 5/9. Winning the award and showing how to simplify, he does it all. A bit of an indirect lesson on fractions, but this book can be used to structure a good lesson on making fractions into simplest form. Not my favorite topic, and certainly not something I’m good at, as math is not my strong suit, but this strange book did intrigue me, and would be sure to do the same with students just to see what happens in the end.
Profile Image for Jessie.
2,048 reviews30 followers
December 27, 2019
The book presents the mechanics of finding fractions that are equivalent to each other pretty clearly (though not with any cleverness about the numbers), but it's really not drawing on images or thinking about the slices that make up fractions here at all.

The story also feels like it cheats to me; the 34/63 is a bit obscured when we see it, so it doesn't appear that there's a missing piece. (You can see the center of the circle, and it *definitely* looks like nothing is missing.) The 1/63 slice is small, it's not something you would overlook in pies of this size.
Profile Image for Sandy.
1,428 reviews3 followers
September 29, 2021
I've been introducing the concept of fractions to my 6 year old... this book may have been a little too advanced. It was entertaining and certainly kept his interest, however, I'm not sure there was much knowledge transfer going on since the book was even a little complicated in the fractions included for me! Once your child has a solid understanding of multiplication and division, then this book is appropriate, otherwise, the reduction of fractions is probably going to create a blank stare.
Profile Image for Jaden Craig.
40 reviews1 follower
April 2, 2020
Factions in Disguise: A Math Adventure by Edward Einhorn is a fun book about a very coveted fraction that vanishes out of thin air. After this mysterious disappearance, George Cornelius Factor then begins doing everything in his power in order to find the missing fraction. I would use this book in my future classroom to introduce simplified and reduced fractions with equal parts in a fun and humorous way.
Profile Image for Kifflie.
1,475 reviews4 followers
July 25, 2020
This is a clever way to introduce the concept of reducing fractions to young students. I think the illustrations showing how 10/15 can be reduced to 2/3 is especially effective to kids who learn more through pictures than operating numbers. It might be a good book to share with a child who is having trouble learning the concept
Displaying 1 - 30 of 48 reviews

Can't find what you're looking for?

Get help and learn more about the design.